"I've discovered that there are some limits to filibustering, and I am going to have to take care of one of those in a few minutes here," he said to laughter after thanking his supporters and staff.

Forcing the question of civil liberties and U.S. drone policy into the spotlight, what began as a one-man stand increasingly gained steam - and supporters - both in the Senate chamber and in social media throughout the day.

Paul's traditional or "talking" filibuster -- dependent on one senator's control of the floor rather than a tally of votes -- continued into the wee hours as the Kentucky lawmaker pressed his case against the administration's policy on drone strikes on American soil.

Sen. Marco Rubio, R-Fla., engages in a discussion with Sen. Rand Paul, R-Ky., over the use of lethal force on American citizens on U.S. soil and the nomination of John Brennan as CIA director on the Senate floor on Wednesday.

It was the first use of the tactic since 2010, when Independent Sen. Bernie Sanders of Vermont held the Senate floor for eight hours and 37 minutes - a length Paul surpassed.

The senator was joined on the floor throughout the day and night by other lawmakers, who stepped in to help continue the filibuster by asking lengthy questions on the Senate floor. His colleagues' contributions also included statements of support, the reading of tweets supporting Paul's efforts and the quoting of rap lyrics, Shakespearean prose and classic Hollywood films.

In a sign that Paul's cause had moved beyond just the most conservative wing of the party, Senate Minority Leader Mitch McConnell - Paul's fellow Kentuckian who is facing re-election in 2014 - joined close to midnight to offer support for Paul's "tenacity and conviction" and to announce that he will oppose CIA nominee John Brennan's confirmation.

Republican Sens. Mike Lee of Utah, Ted Cruz and John Cornyn of Texas, Jerry Moran of Kansas, Saxby Chambliss of Georgia, Pat Toomey of Pennsylvania, Marco Rubio of Florida, Jeff Flake of Arizona, Ron Johnson of Wisconsin, Tim Scott of South Carolina, John Thune of South Dakota and John Barrasso of Wyoming -- as well as Democrat Ron Wyden of Oregon -- also participated.

The filibuster continued late into the night despite earlier Democratic attempts to defuse it.

First, Paul rebuffed Majority Leader Harry Reid's attempts to move to a vote on the nomination, pushing the final vote at least until Thursday.

Hours later, Democratic Whip Dick Durbin of Illinois objected to Paul's request that the Senate take up a non-binding sense of the Senate resolution stating that the U.S. government cannot target "noncombatants" with drones on American soil.

Arguing that such a resolution would be premature, Durbin instead invited Paul to testify at an upcoming hearing on the issue of drones.

But that offer was not enough for Paul to halt his protest.

Paul objects to what he calls the Obama administration's lack of clarity over whether a suspected terrorist who is an American citizen can be targeted with a drone strike within U.S. borders.

In a response to a letter of inquiry, Attorney General Eric Holder wrote to Paul this week that such a targeted strike is "possible, I suppose" in a catastrophic circumstance, although the administration has "no intention" of doing so.

Paul began his filibuster as Holder testified before the Senate Judiciary Committee, where the attorney general reiterated some of that defense of the administration's policy.

Hours into his filibuster, Paul acknowledged that Brennan is still likely to be confirmed, saying the lengthy delay is merely a "blip" in his nomination. But he and other participants emphasized that the debate is intended to shine a spotlight on the government's balance of civil liberties with national security.

Over six hours after beginning the filibuster, a visibly tired Paul could be seen eating what appeared to be several pieces of candy in between sentences. At one point, Sen. Mark Kirk, R-Ill., set a thermos and an apple on his desk.

"You must surely be making Jimmy Stewart smile," Cruz said of Paul upon taking the floor, alluding to the famous filibuster portrayed by the actor in the 1939 film "Mr. Smith Goes to Washington."